Various catalysts based on combinations of titanium oxides and zinc oxides are known. For example, U.S. Pat. No. 5,254,596 to Irick, Jr., et al., discloses titanium-zinc oxide catalysts and the use of the catalysts in the manufacture of methanol and dimethyl ether. U.S. Pat. No. 5,624,667 to Maruo discloses titanium oxide particles comprising particulate titanium oxide substrate having a zinc oxy compound or a combination of a zinc oxy compound and a silicon oxy compound supported thereon. The particles are taught as being useful for pigments, catalysts, catalyst supports and absorbents.